Sound art is an odd thing. Listen to the representation of a sound art piece on LP or CD, the carrier object for the auditory component of that double-pronged “genre,” and you’re missing the experiential and spatio-temporal dimensions of the work, its sited-ness in space. At its best, the recorded artifact can suggest another way of hearing sound art, but more often than not, it ends up as a dry and unappealing misrepresentation. But go and observe a sound art piece in installation mode and you’re immediately in thrall to the visual aspects of sound art, such that the sound component often scuttles into the corner of the room, downgraded from artist’s raison d’etre to audience member’s afterthought — no matter how many framing devices try to mitigate this outcome.

Christina Kubisch’s works sit a little uneasily in this world, simply because she’s one of the few sound artists who’ve managed to get the balance right between sound object and physical object. Practicing since the ‘70s, she hit her stride in the following decade. After studying electronics in Milan, she began working with magnetic induction and electro-magnetic field recordings, the latter of which makes up the content of Magnetic Flights. She may be best known for her Electronic Walks, where audience members wear headphones specially designed to amplify the currents of electricity that buzz and whirr through the cityscape. (See Alan Licht’s Sound Art for great photos of headphone-wielding pedestrians leaning in for a closer listen to the sound of modern capitalism, the humming of the ATM.) Fabulously described by Christoph Metzger as “absurd cartographies,” the Electronic Walks are among the few sound art works that lend an ear to psycho-geography: a “network topology of a phantom city,” if you will.

With Magnetic Flights, Kubisch records the electro-magnetic fields of modern transport and then re-composes them into gorgeous blocks of monochrome hum. Both the title track and “In Transition” are livid things, generating a fluorescing phosphor for the ears, weaving abraded blocks of buzzing electronics — real electronics — together into heavy drone structures. “Magnetic Flights,” as the title implies, focuses on airports, where “In Transition” brings train and bus stations and other points of congregation to bear on the audio spectrum. The latter is thus busier, more surprising — you will find yourself double-checking your mobile for a missed call, the first time the inimitable electronic stutter of mobile phone interference whispers through the speaker cone.

“In Transition” loses a little for being a stereo mixdown of an eight-channel sound installation (originally presented in Texas as Memory Room), and “Ocigam Trazom” on Mono Fluido suffers a similar fate. More problematic is Kubisch’s avoidance of the political resonance of the modern airport as spaces of exclusion, border-crossing, “security,” and definition of legal and “illegal” entry. This is something that has been taken up by other artists, like Ultra-Red and Terre Thaemlitz, in critical sound pieces that question the way borders define selves (see, for example, Thaemlitz’s analogous reading of border-crossing and cross-dressing in Trans-Sister Radio). While Kubisch herself has stated that she is not so interested in the polemical — quoted in David Toop’s Haunted Weather, she defines herself against the eco-politics of R. Murray Schafer, stating “It’s too strident and pregnant with symbolism… I don’t want to make demands on the listener in advance.” There’s also a need to be careful of the quiet sublimation of the political dimension of sound art, which is endemic to the field.

While Magnetic Fields offers us a welcome chance to connect with Kubisch’s current practice, Mono Fluido gives us a welcome history lesson. Originally constructed to accompany film by collaborator Fabrizio Plessi and then subsequently re-worked when Kubisch “felt the desire to make a new piece out of the material, which would be free of the limitations of a cinematic soundtrack,” “Mono Fluido” itself is the most compelling of the four pieces across these two Kubisch discs. Whether this is due to its dissociation from the visual … well, I have my suspicions, but regardless, it’s one of Kubisch’s loveliest pieces, with flute, field recordings, human breathing and electronics hanging together as if suspended amongst the “swinging plastic tubes” that also make up part of the sound field. Patient and perpetually receding into near silence, it has a beautiful sense of stasis, but without the craw-sticking religiosity of similar composers who hover at the edge of audibility — I am thinking particularly of Arvo Pärt.

“Ocigam Trazom” (scan it backwards) is Kubisch’s short rendering of an installation created in response to Mozart’s The Magic Flute. There’s something wonderful in her response to Mozart, stripping his opera of all its performativity and grandiosity, and instead placing it in a near-empty, plain-white architectural space. Using the “activated headphone” that came to define her work, Kubisch placed the listener with ‘phones in a large space in which were strung 16 cables and through which she broadcast a selection of disparate sounds that reflected the eight main characters of the opera. There’s a magical moment in the stereo mixdown where an operatic voice fights to be heard among the electronic clamor and sigh of the other materials used in the piece. An object lesson in how to do sound installation right, “Ocigam Trazom” nonetheless also suffers from lacking what one imagines would be the dynamic tensions at play when you’re actually embedded as an audience member within the installation space.

None of which brings us to Ellen Fullman, who deserves a much better fate than being consigned to the end of this review, though correlating release dates have a way of doing that to artists. There’s not that much connecting Fullman to Kubisch, though the long cables of “Ocigam Trazom” find an echo in Fullman’s 50-foot “long string instrument,” and Fullman has a background in sculpture, which similarly carves up physical space in unexpected ways. But where Kubisch comes from “sound art,” Fullman is from the “art of sound,” and the resonant tremble of strings leads her compositions. Through Glass Planes undergoes disarmament as it plays out — from duo and trio performances to start, Fullman then pares things back to the essence, the long string instrument itself. By the time we reach “Event Locations No 2,” the whole room is singing with tone.

But first, those duo and trio recordings, both extrapolations on compositions from Fullman’s Stratified Bands: Last Kind Words. Based on Geeshie Wiley’s “Last Kind Words Blues,” but using as its structural basis the kinds of ornamentation found in North Indian vocal music, both “Never Gets Out Of Me” and “Flowers” allow for interesting contrasts, with (respectively) cello, or cello and violin, weaving in between those long strings. Theresa Wong’s cello on “Never Gets Out Of Me” is particularly arresting, tracing cellular melodies through the air, recalling — rather surprisingly — the micro-melodies that fall from the air and quietly disturb the near-silent surfaces of Morton Feldman’s Rothko Chapel. The difference is, Feldman never had the ring and snarl of long strings playing out behind him, and on “Never Get Out Of Me,” in particular, Fullman really channels the lassoing spirit of the tambura in her deft playing of the long strings.

On the title track, Fullman moves from melody to rhythm, using the box bow (“a hand held hollow wooden box with a curved lower surface”) to drum out simple rhythmic patterns on the instrument. Watching her do this via her BAMPFA interview, the box bow looks like a strangely metamorphosed e-bow, tapping out Just Intonated chords that sing out in strange pulses. It’s arresting enough, but just a prelude for the aforementioned “Event Locations No 2,” where Fullman uses pitches based on two tuning systems to generate slow-moving, psycho-active sum and difference tones. Denuded of everything but the singing of the strings themselves, this is Fullman at her peak, the unadorned beauty of the instrument playing secret melodies that appear as though they had particlized, drifted through the air and then re-assembled along the long strings.